Warn about code that uses variables and functions with internal linkage

without defining them.  This should be an error, but I'm paranoid about
"uses" that end up not actually requiring a definition.  I'll revisit later.

Also, teach IR generation to not set internal linkage on variable
declarations, just for safety's sake.  Doing so produces an invalid module
if the variable is not ultimately defined.

Also, fix several places in the test suite where we were using internal
functions without definitions.

llvm-svn: 126016

1 files changed, 14 insertions, 2 deletions

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index d5e9dbf4fc7..7d4b461f5a7 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -637,14 +637,26 @@ void NamedDecl::ClearLinkageCache() {
   if (const CXXRecordDecl *record = dyn_cast<CXXRecordDecl>(this))
     clearLinkageForClass(record);
 
-  if (const ClassTemplateDecl *temp = dyn_cast<ClassTemplateDecl>(this)) {
+  if (ClassTemplateDecl *temp =
+        dyn_cast<ClassTemplateDecl>(const_cast<NamedDecl*>(this))) {
     // Clear linkage for the template pattern.
     CXXRecordDecl *record = temp->getTemplatedDecl();
     record->HasCachedLinkage = 0;
     clearLinkageForClass(record);
 
-    // ...do we need to clear linkage for specializations, too?
+    // We need to clear linkage for specializations, too.
+    for (ClassTemplateDecl::spec_iterator
+           i = temp->spec_begin(), e = temp->spec_end(); i != e; ++i)
+      i->ClearLinkageCache();
   }
+
+  // Clear cached linkage for function template decls, too.
+  if (FunctionTemplateDecl *temp =
+        dyn_cast<FunctionTemplateDecl>(const_cast<NamedDecl*>(this)))
+    for (FunctionTemplateDecl::spec_iterator
+           i = temp->spec_begin(), e = temp->spec_end(); i != e; ++i)
+      i->ClearLinkageCache();
+    
 }
 
 Linkage NamedDecl::getLinkage() const {